Field
Isotopically modified polyunsaturated lipids, mixture of isotopically modified polyunsaturated lipids, methods of making such compounds or mixture, pharmaceutical compositions and medicaments comprising such compounds or mixtures, and method of using such compounds or mixtures to treat, prevent, alleviate, or diagnose disease, disorders, or conditions are provided. Isotopically modified 1,4-diene systems such as polyunsaturated fatty acids (“PUFAs”) are also disclosed.
Description of the Related Art
Oxidative damage is implicated in a wide variety of diseases including, but not limited to, mitochondrial diseases, neurodegenerative diseases, neurodegenerative muscle diseases, retinal diseases, energy processing disorders, kidney diseases, hepatic diseases, lipidemias, cardiac diseases, inflammation, and genetic disorders.
While the number of diseases associated with oxidative stress are numerous and diverse, it is well established that oxidative stress is caused by disturbances to the normal redox state within cells. An imbalance between routine production and detoxification of reactive oxygen species (“ROS”) such as peroxides and free radicals can result in oxidative damage to cellular structures and machinery. Under normal conditions, a potentially important source of ROSs in aerobic organisms is the leakage of activated oxygen from mitochondria during normal oxidative respiration. Additionally, it is known that macrophages and enzymatic reactions also contribute to the generation of ROSs within cells. Because cells and their internal organelles are lipid membrane-enveloped, ROSs can readily contact membrane constituents and cause lipid oxidation. Ultimately, such oxidative damage can be relayed to other biomolecules within the membrane and the cell, such as proteins and DNA, through direct and indirect contact with activated oxygen, oxidized membrane constituents, or other oxidized cellular components. Thus, one can readily envision how oxidative damage may propagate throughout a cell give the mobility of internal constituents and the interconnectedness of cellular pathways.
Lipid-forming fatty acids are well-known as one of the major components of living cells. As such, they participate in numerous metabolic pathways, and play an important role in a variety of pathologies. Polyunsaturated Fatty Acids (“PUFAs”) are an important sub-class of fatty acids. An essential nutrient is a food component that directly, or via conversion, serves an essential biological function and which is not produced endogenously or in large enough amounts to cover the requirements. For homeothermic animals, the two rigorously essential PUFAs are linoleic (cis,cis-9,12-Octadecadienoic acid; (9Z,12Z)-9,12-Octadecadienoic acid; “LA”; 18:2;n-6) and alpha-linolenic (cis,cis,cis-9,12,15-Octadecatrienoic acid; (9Z,12Z,15Z)-9,12,15-Octadecatrienoic acid; “ALA”; 18:3;n-3) acids, formerly known as vitamin F (Cunnane S C. Progress in Lipid Research 2003; 42:544-568). LA, by further enzymatic desaturation and elongation, is converted into higher n-6 PUFAs such as arachidonic (AA; 20:4;n-6) acid; whereas ALA gives rise to a higher n-3 series, including, but not limited to, eicosapentaenoic acid (EPA; 20:5;n-3) and docosahexaenoic (DHA; 22:6;n-3) acid (Goyens P L. et al. Am. J. Clin. Nutr. 2006; 84:44-53). Because of the essential nature of certain PUFAs or PUFA precursors, there are many known instances of their deficiency and these are often linked to medical conditions. Furthermore, many PUFA supplements are available over-the-counter, with proven efficiency against certain ailments (See, for example, U.S. Pat. No. 7,271,315 and U.S. Pat. No. 7,381,558).
PUFAs endow mitochondrial membranes with appropriate fluidity necessary for optimal oxidative phosphorylation performance. PUFAs also play an important role in initiation and propagation of the oxidative stress. PUFAs react with ROS through a chain reaction that amplifies an original event (Sun M, Salomon R G, J. Am. Chem. Soc. 2004; 126:5699-5708). However, non-enzymatic formation of high levels of lipid hydroperoxides is known to result in several detrimental changes. Indeed, Coenzyme Q10 has been linked to increased PUFA toxicity via PUFA peroxidation and the toxicity of the resulting products (Do T Q et al, PNAS USA 1996; 93:7534-7539). Such oxidized products negatively affect the fluidity and permeability of their membranes; they lead to oxidation of membrane proteins; and they can be converted into a large number of highly reactive carbonyl compounds. The latter include reactive species such as acrolein, malonic dialdehyde, glyoxal, methylglyoxal, etc. (Negre-Salvayre A, et al. Brit. J. Pharmacol. 2008; 153:6-20).
A logical way to obviate the damage associated with ROS would be to neutralize them with antioxidants. However, the success of antioxidant therapies has so far been limited. This may be due to several reasons, including (1) the near-saturating amount of antioxidants already present in living cells and the stochastic nature of the ROS inflicted damage, (2) the importance of ROS in cell signaling and hormetic (adaptive) upregulation of protective mechanisms, (3) the pro-oxidant nature of some antioxidants such as vitamin E, (4) the non-radical nature of PUFA peroxidation products, which can no longer be quenched with most antioxidants.